1. Field of the Invention
The present invention generally relates to an image forming apparatus such as a copier, a printer, a facsimile machine, and a multifunction machine including at least two of these functions.
2. Discussion of the Background Art
There are image forming apparatuses, such as copiers, printers, facsimile machines, etc., that are provided with an image reading part, such as a scanner, located above an apparatus body in which an image forming part is included.
In one related-art example of an image forming apparatus, an upper cover is pivotally attached to an apparatus body so as to be openable and closable with respect to the apparatus body, and an image reading part is mounted on the upper cover. The image reading part includes a pressure plate or an automatic document feeder (ADF) that serves as a document press member to hold an original document to be read. The pressure plate is rotatable so as to be openable and closable with respect to the housing of the image reading part.
If the upper cover and the pressure plate are configured to rotate in an identical direction, the pressure plate might rotate in conjunction with opening of the upper cover. If the pressure plate opens accidentally, the impact of the pressure plate might damage the upper cover, and/or the pressure plate might hit a user.
Therefore, such an image forming apparatus includes a platen lock that is interlocked with opening of the upper cover and prevents the pressure plate from opening. For example, the platen lock includes a lock claw that engages and disengages from an engagement part provided on the pressure plate in conjunction with opening and closing of the upper cover, respectively, thus preventing the pressure plate from opening accidentally.
Further, there are image forming apparatuses that use a space between an upper cover and an image reading part as a sheet stack part or sheet discharge part. However, if the image reading part is located over or above the sheet discharge part to make the image forming apparatus compact, it is difficult to remove and even to see the sheets on the sheet stack part.
Therefore, in another related-art example of an image forming apparatuses, an image reading part is mounted on an upper cover slidably in a direction that exposes part of the sheet stack part.
However, when the image reading part is slidably mounted on the upper cover, relative positions of the image reading part and the apparatus body depend on sliding of the image reading part. In such a case, the platen lock described above is not usable.